I need to test a console application and check printed output, using rspec script. Example:
RSpec.describe 'Test Suite', type: :aruba do
it "has aruba set up" do
command = run("echo 'hello world'")
stop_all_commands
expect(command.output).to eq("hello world\n")
end
It fails with:
Failure/Error: command = run("echo 'hello world'")
`run` is not available from within an example (e.g. an `it` block) or from constructs that run in the scope of an example (e.g. `before`, `let`, etc). It is only available on an example group (e.g. a `describe` or `context` block).
Aruba version 0.14.6, Rspec 3.7.0. Will appreciate any help. Thanks.
As the error implies, you cannot call run within the it block. Aruba's documentation can get a bit confusing here because of the various branches, but the run method is still available in the still branch, with documentation found here.
Following the documentation, instead of defining command within the it block, we can instead define it outside the block using let:
RSpec.describe 'Test Suite', type: :aruba do
context "aruba test" do
let(:command) { run("echo 'hello world'") }
it "has aruba set up" do
stop_all_commands
expect(command.output).to eq("hello world\n")
end
end
end
Related
I have a Ruby project with a UNIX executable file called parse located in a bin subfolder in my project root directory.
At the moment it's just this:
#!/usr/bin/env ruby
# frozen_string_literal: true
puts 'hello world'
The file can be executed on the command line when this command is run from the project root directory: bin/parse
It works fine, but I also want to write a passing Rspec test for it.
I have this spec file:
RSpec.describe "end-to-end application behaviour" do
subject { system('bin/parse') }
it 'prints the expected messsage to stdout' do
expect { subject }.to output(
'hello world'
).to_stdout
end
end
When I run it I get the test failure:
expected block to output "hello world" to stdout, but output nothing
This is the location of my spec file relative to my project root: spec/integration/parse_spec.rb
I tried placing require and require_relative statements in that spec file with the paths to the parse executable, in case that would help, but I just kept getting:
LoadError: cannot load such file
Does anyone know how I can write a test in that file that will pass and prove the parse executable behaviour works?
Don't Use the RSpec Output Matcher
RSpec has a built-in output matcher than can test both where output goes, as well as its contents. However, it's testing where your Ruby output goes, not whether some external application is using standard input or standard error. You're going to have to make some different assumptions about your code.
You can avoid driving yourself nuts by comparing strings rather than testing the underlying shell or your output streams. For example, consider:
RSpec.describe "parse utility output" do
it "prints the right string on standard output" do
expect(`echo hello world`).to start_with("hello world")
end
it "shows nothing on standard output when it prints to stderr" do
expect(`echo foo >&2 > /dev/null`).to be_empty
end
end
Just replace the echo statements with the correct invocation of parse for your system, perhaps by setting PATH directly in your shell, using a utility like direnv, or by modifying ENV["PATH"] in your spec or spec_helper.
As a rule of thumb, RSpec isn't really meant for testing command-line applications. If you want to do that, consider using the Aruba framework to exercise your command-line applications. It's best to use RSpec to test the results of methods or the output of commands, rather than trying to test basic functionality. Of course, your mileage may vary.
Use to_stdout_from_any_process instead of to_stdout:
expect { subject }.to output('hello world').to_stdout_from_any_process
Is there a Ruby Cucumber test hook for at_start? I tried at_start and it didn't work.
I have something like this in support/hooks.rb and I want to print a single global message before any of the tests start:
Before do
print '.'
end
at_exit do
puts ''
puts 'All Cucumber tests finished.'
end
It seems like if they have an at_exit hook, they should have a before-start hook as well right?
There is some documentation for "global hooks" at https://github.com/cucumber/cucumber/wiki/Hooks
You don't need to wrap it in any special method such as Before or at_exit. You just execute the code at the root level in any file contained in the features/support directory, such as env.rb. To copy and paste the example they've given:
# these following lines are executed at the root scope,
# accomplishing the same thing that an "at_start" block might.
my_heavy_object = HeavyObject.new
my_heavy_object.do_it
# other hooks can be defined in the same file
at_exit do
my_heavy_object.undo_it
end
They also give an example of how to write a Before block that gets executed only once. Basically you have this block exit if some global variable is defined. The first time the block is run, the global variable is defined which prevents it from being executed multiple times. See the "Running a Before hook only once" section on that page I linked.
New to rubby and rspec i am trying to test a class that opens and write to a file.
The class name is SimpleLogger
Here is the spec that generates an error:
describe SimpleLogger do
...
context 'when using a file' do
require 'fakefs/spec_helpers'
before(:all) do
#path = 'my_file'
logger = SimpleLogger.new #path
logger.write "Hello, world!"
logger.close
end
...
it 'we expect the file to have a valid content' do
expect(File.read(#path)).to eq "Hello, world!\n"
end
end
end
The error generated is:
Failure/Error: expect(File.read(#path)).to eq "Hello, world!\n"
expected: "Hello, world!\n"
got: ""
(compared using ==)
Diff:
## -1,2 +1 ##
-Hello, world!
The file exists on my file system, and when I'm testing a simple puts Find.read("my_file") on an independant ruby file i've got the expected result.
I've tested and have the same issue without the fakefs gem
Why is it when run in a spec it doesn't work?
And beside that i fail to understand the advantage of fakefs, as it creates the file juste the same. So why fakefs is used?
And as it creates the file should i erase it within the spec?
Thanks in advance ;)
From the documentation - it seems that you need to include the helpers to activate the FakeFS:
FakeFS::SpecHelpers provides a simple macro for RSpec example groups to turn FakeFS on and off.
To use it simply require 'fakefs/spec_helpers', then include FakeFS::SpecHelpers into any
example groups that you wish to use FakeFS in. For example:
require 'fakefs/spec_helpers'
describe "Some specs that deal with files" do
include FakeFS::SpecHelpers
...
end
By default, including FakeFS::SpecHelpers will run for each example inside a describe block.
If you want to turn on FakeFS one time only for all your examples, you will need to
include FakeFS::SpecHelpers::All.
Alternatively, you can include FakeFS::SpecHelpers in all your example groups using RSpec's
configuration block in your spec helper:
require 'fakefs/spec_helpers'
Spec::Runner.configure do |config|
config.include FakeFS::SpecHelpers
end
If you do the above then use_fakefs will be available in all of your example groups.
You will also need to use before(:each) instead of before(:all) - like many unit test helpers, FakeFS adheres to unit-test isolation principles, in which side-effects of one test should not affect another's. That is why after every test, the gem 'resets' the state of its container, and clears all files from it.
Both examples are going to STDOUT, but cucumber only sees the first one. The second scenario fails with:
Then the stdout should contain "test" # aruba-0.4.11/lib/aruba/cucumber.rb:82
expected "" to include "test" (RSpec::Expectations::ExpectationNotMetError)
features/test.feature:13:in `Then the output should contain "test"'
The features:
Scenario: echo test
Given a blank slate
When I run `echo "test"`
The stdout should contain "test"
Scenario: puts test
Given a blank slate
When I start the program
The stdout should contain "test"
The step definitions:
When /^I start the program$/ do
TestModule::Main.new.start
end
The code:
module TestModule
class Main
def initialize
end
def start
$stdout.puts "test"
end
end
end
I'm not that familiar with Aruba, but a quick peek into it's source code suggests that the assertions it makes against STDOUT (or any output) only apply to processes that it started itself, and not all content that's been written to STDOUT. The code that you invoke yourself, in the second scenario, is outside of the control of Aruba, so it's output won't be tracked.
If you think about it, it couldn't really work any other way - if Aruba captured all STDOUT for assertions, then it would contain Cucumber's own test output as well...
It looks like you're trying to test your program in-process without using Aruba to invoke a separate Ruby process. If that's the case I'd suggest modifying the program to make it possible to pass in a STDOUT replacement e.g.
def initialize(output=$stdout)
Then when you start the code:
When /^I start the program$/ do
TestModule::Main.new(#output).start
end
And you can change your assertion:
Then the stdout should contain "(.+)" do |string|
#output.should include string
end
I have three RSpec2 test files, each of which passes individually. But running the suite with rspec spec (or jruby -S rspec spec) fails.
The problem: ARGV is being set to ["spec"] and running my program with a spec argument changes its behavior. I try to handle this in my tests with:
before(:each) do
ARGV.clear # also tried: ARGV.delete_if { |val| true }
end
but the puts ARGV statement in my code indicates ARGV is still being set to ["spec"].
I've also created a spec/spec_helper.rb file with:
RSpec.configure do |config|
config.before(:suite) do
ARGV.clear
end
end
with the same result. When I run tests individually, ARGV is empty. But when I run rspec spec, ARGV is ["spec"].
Possibly relevant background: I'm running under rbenv.
Rewrite your code such that ARGV isn't mentioned in the methods you're testing.
For example, if you need to test that you can parse "play_jukebox", then do
def test_play_jukebox
parse_options(["play_jukebox"])
end
and in your bin file, have
if $0 == __FILE__
parse_options(ARGV)
end